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Subject: Re: Singleton Pattern
Date: Sat, 13 Aug 2011 14:41:55 -0700
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On 8/13/2011 1:56 PM, vbhavsar@gmail.com wrote:
> The synchronized createInstance() method would eliminate the need to
> do double-checked locking


Nope, it's worse than standard double checked field and therefore 
broken.  Checking once outside of a synchronization block doesn't do 
anything, it's still a read of an unsynchronized field.

That's why singleton patterns are often complicated, they're trying to 
do something difficult.


See the comments I added to your snippet below.


 > 	public static Singleton getInstance(){
 > 		if (_instance == null){  // unsafe check
 > 			createInstance();
 > 		}
 > 		return _instance;